diff --git a/libsrc/runtime/incsp2.s b/libsrc/runtime/incsp2.s
index 959294326..9893bebdc 100644
--- a/libsrc/runtime/incsp2.s
+++ b/libsrc/runtime/incsp2.s
@@ -14,8 +14,12 @@
 	ldy  	#1
    	lda	(sp),y		; get hi byte
        	tax	     		; into x
+.ifpc02	
+	lda	(sp)		; get lo byte
+.else
    	dey
    	lda	(sp),y		; get lo byte
+.endif
 
 .endproc
 
diff --git a/libsrc/runtime/sub.s b/libsrc/runtime/sub.s
index 9108b2710..1cefd9ac7 100644
--- a/libsrc/runtime/sub.s
+++ b/libsrc/runtime/sub.s
@@ -5,7 +5,7 @@
 ;
 
        	.export		tossuba0, tossubax
-	.import		addysp1		
+	.import		addysp1
 	.importzp	sp, ptr1
 
 ;
@@ -15,14 +15,19 @@
 tossuba0:
 	ldx	#0
 tossubax:
-	ldy	#0
 	sta	ptr1
 	stx	ptr1+1
-	lda	(sp),y		; lo byte
-	sec
+.ifpc02
+      	lda	(sp),y		; Get lo byte
+      	ldy	#1		; Hi index
+.else
+      	ldy	#0
+      	lda	(sp),y		; Lo byte
+      	iny			; Hi index
+.endif
+	sec			   
 	sbc	ptr1
 	sta	ptr1		; save lo byte
-	iny
 	lda	(sp),y
 	sbc	ptr1+1
 	tax